Coastal Flood — Kuskokwim Delta Coast and Nunivak Island, Alaska

2025-10-12 · Kuskokwim Delta Coast and Nunivak Island, Alaska

Event narrative

Storm surge from strong southwesterly onshore winds brought water levels to over 6 feet above the normal highest tide line along the Kuskokwim Delta coast during the morning high tide October 12. Water levels peaked in Kwigillingok at 6.3 ft above the normal highest tide line. This surge was more than twice the previous record of 3.1 ft set in 1990. The Kipnuk gage datum recorded water levels of 5.86 ft above the normal highest tide line before the instrument experienced an outage (the actual crest was likely higher). Houses floated off of their foundations in numerous communities including Nightmute, Chefornak, Kipnuk, Kwigillingok, Kongiganak, Tuntutuliak, and Quinhagak. In Kwigillingok, an estimated 37 homes drifted from their foundation, and a preliminary assessment indicates every home in the community was affected {by flooding}. Additionally, 24 people had to be rescued from two houses floating out to sea. In one instance reported on social media from Kipnuk, a house floated 5.5 miles from its original location. 121 homes were destroyed in Kipnuk, an estimated 90% of the community's homes. 17 houses were affected in Nightmute, with some drifting from their foundation. 2 businesses and 15 fish camp structures were displaced or damaged. Hundreds sheltered in community schools during the storm, and in the aftermath around 1,400 were displaced from their homes and stayed at community shelters across the Y-K Delta awaiting evacuation. More than 570 people were evacuated to shelters in Anchorage in the following days, while others chose to shelter in either Bethel, or with family/friends across the state (these displacements will continue through the winter months). Numerous boardwalks were damaged or floated away, while in Kipnuk and Kwigillinok, all boardwalks were destroyed, eliminating essential community infrastructure relied upon in the tundra. Sewer systems and wells were damaged, and several communities lost power due to the storm. Freezers and large subsistence food stores for the winter were also lost in the flooding, eliminating locals' food supply. 1 death was reported in Kwigillingok by state troopers, with 2 still missing (as of 12/3/25). In Kipnuk, 1 injury was reported, 18 people had to be rescued, and the airport runway was cracked, preventing fixed wing aircraft from landing. In Quinhagak, the Alaska State Emergency Operations Center (SEOC) reported that a house was about to tip over from coastal erosion and that a VPSO had helped to rescue people. A raw water line was severely damaged and several houses moved. Additionally, the SEOC reported that: in Kongiganak around three houses were lifted off their foundations, a boardwalk leading to the school vanished (reported by Milton Bunyan, tribal police officer), and a water plant went out of service due to downed powerlines; in Chefornak some houses moved off of their foundations; in Toksook Bay the community lift station had flooded; and in Tuntutuliak houses had moved off their foundations. Two other significant impacts due to this event include salt water intrusion of many community water supply wells, leading to a long-term reliance on outside water supplies, while in both Kipnuk and Kwigillinok, cemeteries were eroded and bodies dislodged, leading to a massive recovery effort in the response.

Wider weather episode

The remnants of Typhoon Halong in the northern Pacific Ocean began approaching the Bering Sea on Saturday, October 11, 2025, as they merged with a deep upper-level low east of Russia's Kamchatka Peninsula. As the systems merged and underwent extratropical transition, the resulting storm was forced northward by a blocking high-pressure ridge over the Gulf of Alaska. Subsequently, the storm's strength increased rapidly as the surface low was steered north toward the western Alaska coastline. Halong's remnants tracked quickly northeast from the Central Aleutians on October 11, across the Seward Peninsula as a hurricane-strength low on October 12, then weakened over the Beaufort Sea early on October 13.

Impacts were first observed across the Pribilof Islands on the evening of October 11, where wind gusts reached 91 MPH as the storm center passed to the west. As the system intensified and moved northeast, it produced widespread damaging winds across the Yukon'Kuskokwim Delta and north through the Brooks Range, with gusts exceeding 100 MPH in some communities. Simultaneously, intense onshore flow drove a record-breaking storm surge into the Yukon'Kuskokwim Delta coast, resulting in catastrophic flooding and destruction across communities from Kongiganak to Hooper Bay.

After reaching a minimum central pressure of 960 millibars (MB) early on October 12, the storm gradually weakened as it tracked northeast, producing additional wind and surge damage across eastern Norton Sound and Kotzebue Sound before dissipating over the Beaufort Sea on Monday, October 13.

What made Ex-Typhoon Halong particularly unusual was fourfold:

1. A long and unobstructed southwesterly storm track;

2. The timing of its rapid intensification as it approached the coastline;

3. The onshore orientation and extreme intensity of its wind field across the Yukon'Kuskokwim Delta and areas north; and

4. The storm's coincidence with the astronomical high tide, which greatly amplified coastal flooding.

In addition, there was no sea ice present in the Bering or Chukchi Seas, leaving the coastline highly vulnerable to wind-driven waves and surge. Collectively, these factors made Ex-Typhoon Halong one of the most significant coastal storms to impact western Alaska in recorded history. In terms of wind energy and coastal inundation, the storm's intensity and effects were comparable to those of a strong Category 2 hurricane.

Source: NOAA Storm Events Database, event_id 1295210. Narrative written by the NWS forecast office that issued the report.